Engine stalling/stumbling problems can be caused by a failing mass airflow sensor.Google+
Car Problem Reports
Volvo 740 Engine Stalling Due to Mass Airflow Sensor Failure
Volvo 740 Problem
Engines Affected: 2.2L 4 Cylinder, 2.3L 4 Cylinder Turbo
Average Mileage: 217,750 mi (209,000 mi - 234,000 mi)
To the anonymous user, before you do anything, remove fuse #1 to reset the engine module, and see how it runs. If it still runs bad, check the fuel pressure, if it's too high, you have a bad fuel pressure regulator. I don't suggest replacing those parts you mention before doing these two things. If yo have any questions, please use our Q&A.
Visitor, 1990 Volvo 740, 2.3L 4 Cylinder Turbo, 214,000 miRookie
Poor engine performance, hard starting, rough cold idle, hesitation, touchy throttle, rich running (poor fuel economy, black soot out tailpipe). Replaced mass airflow sensor after testing it with multimeter, also a trouble code was in there.
Performance, engine response, fuel eco all better,
...BUT still hard starting when cold and no fast idle. Seems to function after 15 seconds, in closed loop mode after things toast up. Probable the engine coolant temperature sensor and oxygen sensor too <(shoot from running rich)?
Visitor, 1991 Volvo 740, 2.3L 4 Cylinder Turbo, 234,000 mi
Visitor, 1990 Volvo 740, 2.3L 4 Cylinder Turbo, 209,000 mi
Acted like it was out of gas. Had a check engine light. Code was for Mass air flow sensor